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Presentation on theme: "BARIATRIC ANAESTHESIA"— Presentation transcript:

(Anesthesia in Obese Patient )


3 Two Worst enemy of Anesthetist

4 Obesity: Definition A condition in which excess body fat may put a person at health risk. (laymen) A chronic metabolic disorder that is primarily induced and sustained by an over consumption or underutilization of caloric substrate (Medical) The American Heart Association (AHA) defines obesity as body weight 30 percent greater than the ideal body weight (Precise)

5 Equations Ideal body weight in Kg (IBW) Body mass index (BMI)
(Broca’s Index) Height in centimeters for men Height in centimeters for women Body mass index (BMI) weight in Kg / height (m) 2


7 Definitions Obese 20% > IBW BMI > 28 – 35 Morbidly Obese 2 x IBW

8 Obesity Classification Overweight - BMI > 25 kg/m2
Obesity - BMI > 30 kg/m2 Morbid obesity – BMI> 40 kg/m2 or 35 with coexisting co morbidities Super obese patient -BMI >50 kg/m2


10 My own BMI My weight is 80 kg My height is 5’8” (170 cm or 1.7 meter)
So my BMI 82 / (1.7)2 is 27.68 So I am Overweight but not obese


12 Incidence of Obesity in INDIA
23 % are obese 5% are morbidly obese Mortality is 3.9 times that in non-obese


14 Causes of Obesity Complex and multifactorial Genetic predisposition
Socialization Age Sex Race Economic status Psychological Cultural Emotional Environmental factors Cessation of smoking

15 Diseases Linked to Obesity
Diabetes Coronary Heart Disease High Blood Pressure ( Hypertension is about 6 times more frequent in obese subjects than in lean men and women ) Stroke Arthritis Gastroesophageal reflux Cancer High cholesterol Endocrine disease A 10-kg higher body weight is associated with a 3.0-mm Hg higher systolic and a 2.3-mm Hg higher diastolic blood pressure. These increases translate into an estimated 12% increased risk for CHD and 24% increased risk for stroke

16 Diseases Linked to Obesity
Hypertrophic Cardiomyopathy Infertility Depression Obstructive sleep apnea Gallstones Fatty liver Stress incontinence Venous ulcers end-stage kidney failure Sudden death

17 Physical Complications of Obesity
Heart disease Type II diabetes mellitus Hypertension Stroke Cancer (endometrial, breast, prostrate, colon) Gallbladder disease Sleep apnea Osteoarthritis Reduced fertility increased risk of morbidity and mortality as well as reduced life expectancy

18 Psychological Complications of Obesity
Emotional distress Discrimination Social stigmatization anxiety, fear, hostility and insecurity

19 Diabetes Mellitus Type 2 prevalence is 2
Diabetes Mellitus Type 2 prevalence is 2.9 times higher in the obese than in non-obese for those years of age. Morbidity due to Cardiovascular diseases has been reported to be almost 90 % in those with severe obesity. Car

20 Cardiovascular Pathophysiology in Obesity
Excess body mass  metabolic demand   CO For every 13.5 kg of fat gained: 25 miles of neovascularization occurs Increased CO of 0.1 L/min for each kg of fat.  workload LVH  pulmonary blood flow and HPV Pulmonary HTN  cor pulmonale  right heart failure

21 Cardiovascular Pathophysiology in Obesity
Stroke volume index and stroke work index are the same as non-obese SV and SW must  Proportion to body weight  SV and SW LVH dilatation

22 Cardiovascular Pathophysiology
 risk of arrhythmias Hypertrophy Hypoxemia Fatty infiltration of cardiac conduction system  catecholamines Sleep apnea dyslipidemia glucose intolerance


24 Cardiac Evaluation: Assess For
Prior MI HTN Angina PVD

25 SAECG (late potentials) ST-T abnormalities ST depression
ECG Changes That May Occur in Obese Individuals   Heart rate   PR interval   QRS interval   or   QRS voltage   QTc interval   QT dispersion   SAECG (late potentials) ST-T abnormalities ST depression Left-axis deviation Flattening of the T wave (inferolateral leads) Left atrial abnormalities False-positive criteria for inferior myocardial infarction

26 Cardiac Evaluation: ECG
Determination of resting rate Rhythm Ventricular hypertrophy or strain

27 Cardiac Evaluation: ECG
Investigate ischemic changes or evidence of coronary artery disease Low voltage ECG Excess overlying tissue Underestimate LVH

28 Cardiac Evaluation: ECG
Axis deviation and atrial tachyarrhythmias Sudden cardiac death is more prevalent with LVH Ventricular ectopy

29 Cardiac Evaluation Indications of LV dysfunction
Limitations in exercise tolerance History of orthopnea Paroxysmal nocturnal dyspnea

30 Vascular Access Challenging at best Central line placement
Excessive fat obscures blood vessels Central line placement Vessels impeded by distortions of the underlying anatomy by adipose.

31 Volume Replacement Adult total body water percentage is 60% to 65%.
Severely obese total body water is 40%. Estimated blood volume in obese patient is 45 to 55 mL/kg actual body weight 70 mL/kg for the non-obese

32 Volume Replacement Avoid rapid rehydration
Lessen cardiopulmonary compromise. Administer Hetastarch at recommended volumes per kilogram of IBW 20 mL/kg Albumin 5% and 25% used as indicated Support circulatory volume and oncotic pressure. Replace blood loss with crystalloid 3:1 ratio

33 Respiratory Pathophysiology
There is a clear association between dyspnea and obesity. Obesity increases the work of breathing because of the reductions in both chest wall compliance and respiratory muscle strength Excess metabolically active adipose +  workload on supportive respiratory muscle  CO2 production Hypercarbia  O2 consumption Hypoxia

34 Respiratory Pathophysiology
Restrictive lung disease Decreased chest wall compliance Diaphragm forced cephalad Decreased lung volumes Accentuated by supine and Trendelenberg positions FRC may fall below closing capacity Alveolar collapse Ventilation / perfusion mismatch

35 Changes in Pulmonary Volumes and Function Tests
Tidal volume Normal or decreased Inspiratory reserve volume Decreased Expiratory reserve volume Greatly decreased

36 Changes in Pulmonary Volumes and Function Tests
FRC Greatly decreased Direct inverse relationship between BMI and FRC FEV1 Normal or slightly decreased

37 Respiratory Pathophysiology
Relatively hypoxemic Occasionally hypercapnic Obesity-hypoventilation (Pickwickian syndrome) Obesity usually extreme Hypercapnia Cyanotic / hypoxemia Polycythemia Pulmonary HTN Biventricular failure Somnolence Obstructive sleep apnea syndrome (OSAS)

38 OSAS Definition Clinically relevant
10 seconds or more of total cessation of airflow despite respiratory efforts Clinically relevant 5 episodes per hour 30 episodes per night

39 OSAS Snoring Dry mouth and short arousal during sleep
Partners report apnea pauses during sleep

40 OSAS More vulnerable to airway obstruction
Opioids Sedatives More vulnerable in supine or Trendelenberg position


42 OSAS and Difficult Intubation
15% of obese patients are a difficult intubation Short thick neck Obesity and short thick neck Related to OSAS and to each other Fat in lateral pharyngeal walls are difficult to exam awake

43 Detecting OSAS Nocturnal polysomnography

44 GI Pathophysiology  incidence Severe risk of aspiration
Gastroesophageal reflux Hiatal hernia  abdominal pressure Severe risk of aspiration

45 GI Pathophysiology After 8 hour fast
85 – 90% of morbidly obese patients have Gastric volumes > 25 ml Gastric pH < 2.5

46 Anesthetic Considerations: Preoperative
 risk for aspiration pneumonitis if reflux history Consider H2 antagonist ( pre, intra and post ) Metoclopramide, Ranitidine or Ondansetron Sleep apnea, asthma, smoking Avoid unnecessary respiratory depressants BHT (breath holding time) Assess for Cardiopulmonary reserve ECG & X-ray Chest, if necessary echocardiography LFT & RFT ABG PFT’s

Obesity: Anesthetic Issues Airway proper positioning can be difficult may need extra support under back POSITION, POSITION, POSITION

48 Anesthetic Considerations: Preoperative
BP with appropriate size cuff Plan / examine for venous / arterial access Possible regional anesthesia

49 Mallampati Classification
Class I = visualization of the soft palate, fauces, uvula, anterior and posterior pillars. Class II = visualization of the soft palate, fauces and uvula. Class III = visualization of the soft palate and the base of the uvula. Class IV = soft palate is not visible at all.

50 Anesthetic Considerations: Preoperative
If HTN – good control Atherosclerosis then ECG &/or Stress Echo Previous anesthesia exposure and any problem to ask

51 Anesthetic Considerations: Preoperative Airway Assessment
Limited TM joint mobility Limited atlanto-occipital mobility Narrow upper airway Small space between mandible and sternal fat pads

52 Neck Circumference Normal neck circumference in cm is weight in kg / 2
Normal neck cir. at 7o kg is 35 cm If it increase by 13 % then difficult intubation is counted

53 Obesity: Anesthetic Issues
Respiratory System high risk of oesophageal reflux (GERD) high risk of aspiration rapid sequence intubation (RSI) indicated pre-oxygenation cricoid pressure succinylcholine

54 Anesthetic Considerations: Induction
Prepare for difficult intubation Prepare for difficult mask ventilation Induction may cause airway collapse Leading to upper airway obstruction

55 Induction Airway Equipment
Light Stylet Gum elastic bougie Oral airway LMA’s ETT with stylet

56 Anesthetic Considerations: Induction
Consider awake intubation Avoids airway collapse Minimal to no sedation LMA is good alternative for temporary mechanical ventilation in grossly and morbid obese patient Consider tracheotomy kit and surgeon standing by

57 Anesthetic Considerations: Intraoperative
Awake fiberoptic intubation if difficult airway suspected Breath sounds distant ETCO2 more important Relatively high FIO2 may be needed in: Lithotomy Trendelenberg Prone

58 VENTILATION In morbidly obese patients, the best strategy for ventilation is to deliver TV according to IBW (8-10 ml/kg ) Apply 5 cm H2O PEEP in order to decrease the incidence of atelectasis. Minute ventilation and ETCO2 need to be monitored closely Usually use pressure control ventilation

59 Best Position for Intubation
External auditory meatus and sternal notch at same level Best Position for Intubation

60 Obesity: Pharmacology
Overdosing of pre medication and anesthesia drugs in obese patient is very common doses should be calculated on predicted “lean body weight” Lean body weight = body weight - fat weight Avoid IM injection due to unpredictable absorption If possible, avoid narcotics and sedation in obese patient

61 Obesity: Pharmacology
Propofol at TBW Thiopental at IBW Midazolam at IBW Scolene at TBW Vcuronium at IBW Atracurium at TBW Rocuronium at IBW Fentanyl & Sufentanyl at TBW Remifentanil at IBW

62 Anesthetic Considerations: Intraoperative
Positioning 2 OR tables side by side If > 350 lbs (150 kg) Prone position is poorly tolerated Lateral decubitus is keeps abdominal weight off chest

63 Anesthetic Considerations: Intraoperative
Morbidly obese patient should never lie flat Semi-Fowler’s position Upper body elevated 30 – 40 Semi-recumbent position Best position during post-operative period

64 Reverse Trendelenburg Position
RTP is best intraoperative position Can ameliorate deleterious effects of supine position RTP is 30 degree head up position RTP  pulmonary compliance  FRC Returned P(A-a)O2 to baseline RTP may be a better solution than Large TV and PEEP Reverse Trendelenburg Position

65 monitoring ECG Pulse Oxymeter Blood pressure Temperature
Inspired oxygen concentration Capnography Arterial catheter to continuously measure BP and blood gases ( if medically indicated ) CVP catheter Urinary catheter Advance monitoring according to Surgery If indicated then BIS

66 A – Anesthesia personnel
M – Machine D – Drug Cart I – Infusion V- Visitor

67 Anesthetic Considerations: Intraoperative
Pulmonary compliance and FRC  Worsened by GETA and high intraabdominal pressure Opening the abdomen or lifting the panniculus  FRC Improves oxygenation

68 Anesthetic Considerations: Intraoperative
Regional anesthesia Technically more difficult Require 20 – 25% less LA for Spinal or Epidural anesthesia because of (Epidural fat and distended epidural veins) Combined epidural/general(GA) preferred to decrease GA requirement Epidural anesthesia may  postoperative respiratory complications

69 Goals for Maintenance of Anesthesia
Strict maintenance of airway Adequate skeletal muscle relaxation Optimum oxygenation Maintenance of anesthesia with inhalation and intravenous agents Avoid residual effects of muscle relaxants Appropriate intraoperative and postoperative tidal volume Effective postoperative analgesia.

70 Anesthetic Considerations: Postoperative
Respiratory failure risk increased by Preoperative hypoxia Thoracic or upper abdominal surgery Vertical incision Delayed extubation until Complete reversal of muscle relaxation Patient fully awake Follows commands

71 Anesthetic Considerations: Postoperative
Supplemental O2 after extubation Transport from OR to Recovery room 45 degree head up position Unload diaphragm Improves oxygenation Improves ventilation CPAP and BiPAP should available

72 Anesthetic Considerations: Postoperative
Increased mortality 6.6% vs. 2.7% in non-obese Absolute no sedation post op Increased risk Wound infection DVT PE

73 Anesthetic Considerations: Postoperative
PCA Can provide good pain relief Dose based on IBW NSAIDs, Local anesthetic infiltration Epidural route is preferred Administration of smaller dose than IV route

74 Airway Management of the Obese
Formulate an airway management plan Facial anatomy needs appropriate mask selection Increased mass of soft tissues and Macroglossia Weight of head Head Tilt & "Sniffing Position" may require building up towels or blankets under the back, scapulae, and shoulders, as well as the head and neck beware of "can’t ventilate, can’t intubate" situations! Mask ventilation may require two persons: one to use two-handed mask technique with triple airway maneuver, airway device, and CPAP; with another to bag the patient and monitor effectiveness appropriately sized oropharyngeal or nasopharyngeal airway "Bull Neck" – short, thick neck inhibits mobility and makes visualization of the larynx difficult during laryngoscopy. Have "rescue" alternative airway devices ready to hand: e.g., Laryngeal Mask Airway (LMA) or Intubating LMA (Fastrach™); Elastic Gum Bougie; Lighted Stylet; Esophageal Combi-Tube™; Fiber-optic Laryngoscope or Bronchoscope

75 Airway Management of the Obese
The first intubation attempt should be by the most experienced intubator If the first best attempt determines difficult or impossible laryngoscopy or intubation, change to either Rescue Airway plan (if patient condition is critical), or early Fiberoptic Intubation before airway trauma worsens the situation Large breasts may get in the way of the laryngoscope handle (half-size handles are available). Response to induction agents is less predictable for intubation Confirmation of endotracheal intubation should be by three or more methods including either capnometry or capnography Obese patients will desaturate oxygen rapidly All obese patients with airway problems or impending intubation should have 100% oxygen In failed Intubation by all methods, in emergency Percutaneous cricothyrotomy or surgical tracheostomy

76 Case study of female obese patient posted for Umbilical Hernia Repair at Sangam Hospital
55 year old female Height 5’2” ( 1.55 meter ) Weight 114 kg BMI 47.5 ASA Physical Status II BP 142/82 mm hg & Resting pulse 82 / mn Spo2 at room air 93 % Mild asthma EF > 50 No other positive personal, past or family history ECG and X-ray chest were normal Lab investigations WNL Negative history of GERD, snoring and obstructive sleep apnea

77 On Examination Very obese patient Very short neck
Mallampati class II airway Patient was needing two pillows in supine Two anesthetist were there Two IV line taken with 20 # veinflon

78 Preparation Pre oxygenation started with 5 liter through nasal prongs
Multi parameter (NK) put including Spo2, ECG, Large BP cuff (NIBP), Temperature probe Patient put supine 30 degree RTP position with 2 pillows under head One nebulizer puff of bronchodilator given

79 Premedication Glycopyrolate 1 ml IV Rantac 2 ml IV Emeset 4 ml
Lyceft 2 gm IV Fentanyl 100 mcg IV Midazolam 2 mg IV Voveran 3ml IV diluted Xylocard 5 ml IV

80 INDUCTION Propofol 1.5 mg / kg IV slowly with total 17 ml given
Immediately put large size oro pharyngeal airway Cricoid pressure applied Spontaneous ventilation maintained and assisted prior to intubation

81 Intubation Cricoid pressure applied Scolene 150 mg given fast IV
Laryngoscopy and Intubation with 7 # cuff ET with stylet were performed uneventfully Cuff pressure 7 ml applied with air Not much threatening changes were noted on multi Para monitor

82 Maintenance Patient put on max ventilator with TV 900 ml ( 8 ml/kg) and RR 16 / min Capnograpgy put between ET and Ventilator Atracurium 50 mg IV bolus Oxygen 3 lit and Nitrous Oxide 3 lit with Isoflurane 2 mark Continuously given Atracurium repeated 15 mg around every 30 minutes No adverse cardiac or respiratory events occurred Total 1500 ml RL given intra operative

83 At the end Nitrous Oxide and Isoflurane discontinued and Oxygen 100 % around 5 lit continued Neuromuscular blockade reversed with neostigmine 5 mg IV and Glycopyrrolate 1 mg IV Mechanical ventilation discontinued upon resumption of spontaneous ventilation

84 Recovery Patient opened eyes and responded to command approximately 5 minutes after reversal. No coughing or breath holding noted Spontaneous ventilation, with sustained head lift and oxygen saturation maintained > 95 % Extubation performed uneventfully Patient transferred to recovery ward in left lateral position with oxygen 3 lit via nasal route Total surgical time was 1 hour 25 minutes and total anesthesia time was 1 hour 40 minutes

85 Transfer Patient put 30 degree head up in recovery room
Patient transferred from recovery to special room after 6 hours No major or life threatening changes in vitals noted in post op period Patient discharged after 8 days

86 Message The anesthetic management of the clinically severe obese patient requires meticulous preoperative, perioperative and postoperative care. Careful planning is essential before taking the patient in the operating room. To have excellent outcome, a multidisciplinary approach, including the primary care physician, anesthesiologist, surgeon, nursing staff and social worker is necessary.


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